| 摘要 |
PROBLEM TO BE SOLVED: To provide a resin-coated heavy duty corrosion-proof steel exerting excellent cathodic separation resistance over a long period even in highly corrosive environments. SOLUTION: A urethane primer layer and a polyurethane corrosion-proof layer are laminated in order on the surface of a substrate steel, with the oxygen permeability of the urethane primer layer at 27°C and a relative humidity of 90% being 1.0 (ml mm)/(m<SP>2</SP>day atm). The urethane primer layer is e.g. a hardened product of a polyol base resin and a polyisocyanate hardening agent, each having a specified composition. The polyol to polyisocyanate mixing ratio in the hardened product is preferably 0.8-2.0 in terms of the ratio of the isocyanate groups in the polyisocyanate to the hydroxy groups in the polyol. COPYRIGHT: (C)2007,JPO&INPIT |
